Purification of liquids



HAROLD S. DAVIS AND SAUL ASSIGNORS TO THE KOPPERS COMPA CORPORATION OF PENNSYLVANIA.

D. SEMENOW, OF PITTSBURGH, PENNSYLVANIA, NY, OF PITTSBURGH, PENNSYLVANIA, A

PURIFICATION OF- mourns.

No Drawing.

To all whom it may concern:

Be it known that-we, HAROLD sr-DAvrs, a subject of the British Empire, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, and SAUL D. SEME- NOW, a citizen of the United States, residing at Pittsburgh, in the county 'of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Purification of Liquids, of which the following is a full, clear, and exact description.

The present invention relates to the purification of liquids and particularly to the purification of the waste liquors from industrial plants so that they may be discharged into streams Wi-thoutpollutin the stream water. The invention is descri edwith particular reference to its embodiment in a proc ess of urifying the waste liquor from the ammonia stills of the by-product coke industry.

It is to. be understood, however, that the invention is not limited in its application to this industry but may be otherwise employed.

Referring to the process as employed for treating the waste ammonia still liquor The raw ammonia still waste has objec-, tionable properties which should be removed before it is discharged into a stream, in order to prevent the pollution of the water thereb 'Phe objectional properties of the ammonla still waste are its harmful eflects on fish, its disagreeable odor, its disagreeable taste and its dark color. 'These properties are largely due to the presence of phenoloid bodies, thiocyanates and sulfids. Small traces of pyridin and other organic compounds not yet identified may contribute to its harmful or disagreeable qualities.

Besides the above impurities there are large quantities of calcium salts, principally calcium chlorid, present in the waste liquor.

owever, since the waste liquor is greatly diluted in the stream to which it is finally drained, the presence of these salts is not particularly ob]ectionable. The present process has to do particularly with the removal the ammonia still waste which give it its harmful effect on fish,

Specification of Letters Patent. Application filed February 15, 1919. Serial No. 277,291.

the liquor. The sulfids exist Patented its disagreeable odor and taste and its dark color.

from the still hot and while hot is aerated, preferably by runnin it through an aeration tower filled with ba l es, coke or other material over which the liquor trickles in contact with the air.

Dec. 2, 1919.

The ammonia still waste liquor is drawn This causes some evap oration of the water and thereby concentrates the liquor to some extent. Italso ermits the evaporation of some of the volatile constituents of the liquid and. thereby gets rid of some of the disagreeable odor. .The aeration of the liquid also causes a more ready precipitation of the solids in the subsequent step of treatment in the settling tank. While it is preferred to aerate the liquor, this step may be omitted.

vThe liquor is nextrun into a settling tank where it remains for about twenty-four hours. During this time about 95% ofjthe precipitable solids settle out of the liquid.

The liquid is drawn next from thesettling tank and filtered through an inorganic'material, preferably granulated blast furnace slag. This filtration completes the removal of the solids which do notsettle out in the ployed contains iron oxids such as are found in the spent slag which results fromthe treatment of mine waterby the process of the Heckman patent, 1,171,046, of February 8th, 1916, the sulfids are also removed from in the liquor rincipally as calcium sulfids. The spent last furnace slag also partially removes some of the cyanogen compounds.

is preferred to use the slag with the iron oxids resulting from the treatment of mine water or the like, the iron oxids might be otherwise supplied to the slag or inorganic filtering material used for this step of the process.

The filtered liquor may then be treated for the removal and recovery of cyanogen compounds. This is' preferably accomplished by .the addition 'to the liquor of a compound such as a ferrous salt which will precl itate the 'ferrocyanids followed by the addition of While it.

cupric sulfate and ferrous sulfate, which results in the precipitation of cuprous thiocyanate. This step may be omitted if desired.

The above recited steps are for the purpose of preliminarily clarifying the liquor, where by the burden placed upon the lignite filter bed is lessened.

The next step in the process isthe treat-' I ment of, the liquor with ground lignite. This is preferably accomplished by filtering the liquor through the lignite.

We have found that a filter bed of ground lignite a foot or more in thickness is satisfactory. Such filtration permits. a rapid treatment of the liquor and effects a maximum removal of the phenoloid bodies wit a minimum of filtering material.

Phenoloid absorbing humus" materials other than lignite may be employed. For example, filtration of the liquor through ground peat will remove the phenoloid bodies, as more specifically described-and claimed in the co-pending application of Dieterle and Semenow, Serial No. 277,181.

This treatment results in the substantialremoval of the remaining impurities which.

give the liquor its harmful qualities, disareeable taste and smell and its dark color.

he water after this treatment is substantially colorless and substantially odorless and when diluted in the stream is non-poisonous to fish life and not harmful to the water for drinking purposes.

Certain industrial waste liquors which contain a minimum of solid impurities, sulfur and cyanogen compounds, for examplethe efiiuents from certain ammonia stills may be treated directly with the lignite without any preliminary treatment of the .ing liquors containing phenoloid bodies,

comprising, filtering the material through a filter bed containing lignite; substantially as described.

2. The herein described process of purifying liquors containing phenoloid bodies,

comprising, filtering the liquor through a filter bed containing ground lignite; sub stantially as described.

-rial; substantially as described.

rsaaaei filter; bed containing av phenol-absorbing humus material; substantially as described.

4. The herein described process of purifying waste ammonia stil liquors, comprising, preliminarily clarifying the liquor and then filtering it through .a filter bed containing a phenol-absorbing humus mate- V 5. The herein described process of purifying waste ammonia still liquors, comprising, preliminarily clarifying the liquor and then filtering it through a filter bed containirig lignite; substantially as described.

e process of purifying waste ammonia still liquors Whichconsists in aerating the liquor, se arating the solids therefrom by settling, ltering the liquor throu h an inorganic filtering material and then l tering the liquor throu h a filter bed con taining a phenol-absor ing humus material; substantially as described.

7. The process of purifying waste am- 1 monia still liquors, comprising, treatingthe liquor with an iron oxid-containing material, and thereafter filtering the liquor through a filter bed containing'a phenolabsorbin humus material; substantially as describe i 8 The process of purifying waste ammonia-still liquors, comprising, filterin the liquor through blast furnace slag andt ereafter filtering the liquor through a filter bed containing a phenol-absorbing humus material; substantially as described 9. The herein described rocess of purifying waste ammonia still liquors, comprising, preliminarily filtering the liquor, removing the cyanogen compounds from the liquor, and thereafter filtering the liquor through a filter bed containing a phenolabsorbin'g humus material; substantially as described. y

10. The process of purifying waste ammonia still liquors which consists in aerat- 1 through a filter bed containing ligtnite; substantially as described.

12. The. process of purifying wasteammonia still liquors, comprising, filtering the rial, and thereafter filtering the liquor T liquor through blast furnace slag and thereafter filtering the liquor through a filter bed 1,323,251 containing ligni'te substantially as dethrough a filter bed Containing Iignite; sub-' scribed. i

V q stantially as described. 13. ,The herein described process of pui'i- In testimony whereof we have hereunto 10 fying Waste ammonia still liquors, comprisset our hands. 5 ing, preliminarily filtering the liquor, re-

( moving the cyanogen compounds from the liquor, and thereafter filtering the liquor HAROLD s. DAVIS. SAUL n. SEMENOW. 

